Conveyor belts of the type described above are often used in air conditioning plants for e.g. quick-freezing of food products.
Such conveyor belts are usually made up of link means which comprise lateral elements and transverse rods connected thereto. The link means are interconnected in such a manner that the conveyor belt is turnable vertically and laterally.
The link means of the conveyor belt may, however, be designed in various ways.
FIGS. 1a–c show a conveyor belt 101 with link means 102 of a first type. Each link means 102 comprises two lateral elements 103 and a rod 104 extended between and fixedly connected to the lateral elements 103.
Elongate holes 105 are formed in the lateral elements 103 to interconnect the link means 102, the rod 104 of a link means 102 extending through the elongate holes 105 in the lateral elements 103 of an adjoining link means 102.
The elongate holes 105 cause adjoining link means 102 to be movable relative to each other. Owing to this movability, the conveyor belt 101 can also be turned in the lateral direction.
The rods 104 are turnably mounted in the elongate holes 105, thus allowing the conveyor belt 101 to turn in the vertical direction.
In vertical turning, which is illustrated in FIG. 1c, the conveyor belt 101 is rigid over two rods 104, which means that the turning radius R1 is dependent on a distance A1 corresponding to the distance between two rods 104.
A conveyor belt constructed according to this principle is described, for instance, in EP 293 095.
This prior-art type of conveyor belt 101, however, suffers from a serious drawback. The link means 102 of the conveyor belt 101 exhibit relatively low rigidity, which means that its load-bearing capacity is limited.
This drawback has been eliminated by means of a conveyor belt 201 as shown in FIGS. 2a–c. The conveyor belt 201 comprises link means 202 of a second type.
This second type of link means 202 comprises lateral elements 203 which are fixedly connected in pairs to two rods 204.
The lateral elements 203 and the rods 204 form a link means 202 with a torsionally relatively rigid frame structure. The link means 202 are in turn interconnected in a manner similar to what has been described above for a conveyor belt 101 with link means 102 of said first type.
A conveyor belt constructed according to this principle is described, for example, in SE 452 590.
In some cases, it is desirable to provide an even stronger connection between the link means 202. It is then also known to connect the link means 202 by means of pull elements (not shown) which are connected with the opposing rods of two adjoining link means 202.
The torsionally relatively rigid link means 202 of said second type imply that the conveyor belt 201 will have a good load-bearing capacity. In some cases, however, the design of the link means causes difficulties.
The design of the link means 202 results in the fact that the conveyor belt 201 when turning in the vertical direction, which is shown in FIG. 2c, becomes rigid over a distance A2 corresponding to three rods 204, and consequently the turning radius R2 of the conveyor belt 201 increases if the distance between the rods 202 is unchanged in relation to a conveyor belt 101 comprising link means 102 of said first type. To retain a given turning radius, which is frequently desirable, the distance between the rods 204 must thus be reduced, which results in a more compact and heavy conveyor belt 201.
Consequently there is a need for an improved conveyor belt with link means of said second type, i.e. a conveyor belt with torsionally rigid link means.